The Protective Effect Of Melatonin On Fetal Rat Brain Suffered From Lipopolysaccharide-induced Intrauterine Infection

Objective To investigate the effects of melatonin(MT) on free radical of fetal rat brain induced by intrauterine infection, so as to explore the neuroprotective mechan-isms of MT.Methods To establish a modal,fetal rat brain damage made by 1ipopolysaccharide (LPS)-induced intrauterine infection.The pregnant Sprague-Dawley rats on day 19 of gestation were divided randomly into three groups: the blank contral group,the intrauterine infection group and the melatonin group. In intrauterine infection group, the pregnant mice received an intraperitoneal(i.p.)injection of LPS(500 ug/kg).In the melatonin group, the mice were treated with LPS 500ug/kg+MT 10mg/kg.then, according the time after injection ,the pregnant mice were divided into three groups respectively:2h, 6h ,12h groups. To remove the fetuses, laparotomy of the pregnant rats was performed.The activities of superoxide dismutase(SOD), glutathione peroxidase(GSH-Px) and the contents of malondial- dehyde(MDA) in fetal brain homogenates were determined. Meanwhile,the pathological changes of brain tissues were observed under light microscope by HE staining.Results Intrauterine infection lowered the activities of SOD,GSH-Px and elevated the contents of MDA in fetal brain homogenates。Meanwhile, these changes in Intrauterine infection group increased progressively by the time of infection. Treatment with MT partly reversed these changes .Conclusion Intrauterine infection produces excessive free radicals which induce fetal brain damage .By the time of infection, fetal brain damage increases progressively.As a powerful scavenger of free radical, MT protects fetal brain against oxidative damage .